Chuck



C. D. CSSIDY July 11, 195o CHUCK Filed Dec. 18, 1944 :NVENmR c ULi/fordI D. Casld BY 247W ATT EY Patented `uly 11, 14950 CHUCK Clifford D. Cassidy, Bridgeport, Conn., assignor to The Bullard Company, a corporation of Connecticut Application December 18, 1944, Serial No. 568,602

4 Claims. (CI. 279-123) This invention relates to work-supporting devices for machine tools such as lathes, and particularly to a new and improved work-chucking mechanism.

Work-chucking devices for lathes and similar machine tools usually include a spindle having reciprocable shoes to which top jaws are adapted to be adjustably mounted for rigidly gripping the work to be machined.

High-production jobs usually include a separate set of top jaws for each substantially difierent diameter of the work that is required to be gripped. Each of these sets is machined so that their gripping surfaces accurately conform to the diameter of the work at the point of gripping. A separate set of top jaws is required for each substantially different diameter to be gripped because any substantial radial movement of the top jaws disrupts the conformity between the gripping surface of the top jaws and the work. Certain jobsA require as many as four or more different chuckings, at each of which the work may be gripped on a substantially different diameter. Additionally, a production job may include similar pieces of dii-ferent dimensions and separate sets of top jaws would be provided for each substantially different gripping diameter of the similar pieces. In production work in particular,

therefore, a great many sets of top jaws may be provided that require quick change-over at periodic intervals.

Prior-known chucking constructions usually employ a plurality of screws for each top jaw arranged in counterbored openings so as not to interfere with the work to be chucked. These screws are arranged to provide maximum rigidity between the shoe and top jaw, and are usually disposed radially of the chuck on which the shoes and jaws are mounted. Where the chuck seat is in a horizontal plane, these counterbored holes fill with chips from the work being machined, requiring much time to remove the chips prior to removing the top jaws from the shoes.

In multiple spindle lathes, when as many as twelve chucks may be employed, and each chuck includes at least three top jaws, a change-over of the top jaws will involve the cleaning of at least two holes for each of as many as thirty-six top jaws and the loosening and tightening of seventytwo screws. The time involved in such a changeover adds materially to the cost of a job and often exceeds the time of actual machining for which the change-over was required.

The principal object of this invention is to provide a work-chucking device that will overcome the above, as well as other difficulties. Other objects include the provision of a chucking device that includes top jaws that are adapted adjustably to be clamped to shoes in such a way that they can be removed with ease and facility; the provision of such a chucking mechanism in which a single adjustable element is provided to effect clamping and unclamping of a top jaw to a shoe; the provision of such a chucking mechanism in which the force incident to chucking the work always reacts directly on an integral part of the top jaws; and the provision of such a, chucking mechanism in which the adjustable element is so located that it will not interfere with the work being chucked or be interfered with by the metal chips removed from the work.

The above, as well as other objects and novel features of the invention, will become apparent from the following specification and accompanying drawing, in which Figure 1 is a top plan view of a chucking mechanism to which the principles of the invention have been applied; and

Figure 2 is a sectional elevational view taken substantially along line 2-2 of Figure 1.

Referring to the drawing, the invention is shown as applied to a work-supporting chuck for a machine tool including a spindle I0 that is adapted to be journaled in plain or anti-friction bearings within the frame of a machine tool. A table II integral with the spindle I0 is adapted to support a frame member comprising lower'and upper members I2 and I3 respectively within which the means for supporting the operating parts of the chucking device are located. The lower and upper portions I2 and I3 are rigidly held together, but are separable along a line I4 for purpose of assembly. The upper portion I3 includes an annular-shaped recess I5 within which an annular-shaped scroll ring I6 is mounted for rotation. The under surface of the scroll ring I6 includes a bevel gear II formed integrally therewith. The lower portion I2 of the frame member is provided with a semi-cylindrical recess I8 having parallel walls extending to the top of the lower portion I2. Another semi-cylindrical opening I9 is provided within the lower member I2, and a similar semi-cylindrical opening 20 is provided in the upperportion I3. The two semi-cylindrical portions form a cylindrical support for a bushing 2I that surrounds one trunnion 2'2 of a bevel pinion 23. The other trunnion 24 of the bevel pinion 23 is journaled in the semi-cylindrical opening I8. The bevel pinion 23 is adapted to mesh with the bevel gear l'l on the scroll ring I3. A square recess 25 is provided in the end of the trunnion 22 for the reception of a wrench, whereby the pinion 23 can be rotated in either direction to thereby rotate the scroll ring I in either direction. There are three such bevel pinions 23 spaced '120 degrees apart about 'the lower member l2 of the frame. The upper member l3 is provided with radially-disposed slots 26 (Fig. l).

being clamped is at all times transmitted di-l rectly to the depending portion 36 integral with the top jaw 32 and does not react on the threads of the screw 38.

Although the various features of the improved chuck have been shown and described in detail -to -f-ully discloseone embodiment-of the invention, it will be evident that numerous changes may be made in such details, and certain fea- In the present instance, three such slots 26 are 10 tures may be used Without others, Without deprovided at 1Z0-degree intervals about the top member i3. Radially-disposed shoes 27 are located in each of the slots 28 and each includes a nut 28 fixed to the shoe 2?.'byfscrews-29. lEach nut 28 cooperates with the scroll on the scroll ring I5 in such manner that upon rotation of the ring IS, shoe 2 is adapted tobeinoved radially relatively to the work-supporting chuck. The lower and upper portions I2 and I3 of the frame are adapted rigidly to be lfixed together by screws 3B. The frame itself is rigidly vfined to the table 'Hy by the screws 3|. A top jaw 32 is provided with -an arcuate gripping surface '33 that is Inachined to accurately conform to the diameter of the work at the point of gripping.

In the present invention, means is Yprovided for rigidly but releasably holding the'top jaw havingthe correct arcuate gripping surface at its parting from the principles of the invention.

What is claimed is: 1. 'A chuck jaw assembly including a support;

, a 'set of equally-spaced transverse grooves on atop -jaw having a single integral binding vprocorrectrradial position along the longitudinal axis-of the shoe 27. Supporting means for top Ijawsi32,4 in the instant disclosure, take the form of shoes 2. These shoes are provided with a plurality 'of transverse slots l3l3, each having a semi-dovetail wall construction, and a`4 plurality of slots of similar construction. YThe construction and arrangement are such that the slots 313 cooperate with slots 35 to provide one portion `of a.V dove-tail clamping means.l Each top jaw 32 includes an integral depending clamp- "ofthe clamping member 3 7 includes a-iiange 39 athat overlies ashoulder 43 on the topy jaw "32, The lower-endof the clamp member 31 includes a semi-dovetail surface adapted to cooperate with a corresponding semi-dovetail surface on the outer endof theshoe 2, as well as with similar 4serni-dovetail surfaces of the slots` 35`` A screw iil -(Fig. 1) is adaptedl to hold a washer i2 on the one side of each shoe 2 to insure proper circumferential positioning of the top jaws during setup. Referring to Fig. 2, the construction-and arrangementof the parts are such that to change over from the top jaw 32 shown, to one that calls for a different location from that shown in Fig. 2,'it is only necessary to loosen screw 38 and to V'shift the topjaw 32v transversely of the shoe 2i faway from'washervZ until the jaw 32 separates therefrom. The newtop iaw 32,`having a dif- -ferent arcuate gripping surface 33 may then be Aslid transversely of the shoe 2'! at its correct lradial location such that the depending l'portion 3i-fof the top jaw slides lwithinV the correct groove 34; thelower portion of the clamp 3i slides withv inthe 'correctgroove' 35; and the one side ofthe jaw 32 engages washer 42. The screw 3 8 on the `newtop jaw may then be tightened to effectively "lar'n'p the jaw to they shoe 21.

AThe construction'ernployed vis"particiilariy` ad- `vntageous since the Arf'ea'ction "from the work jection, of a lwidth less than the width of said transverse grooves and ainating surface for the inclined surface of said grooves; a binder separate from said top jaw including a p'orti'on having a thickness less than -the `width 'of said grooves and a 'mating surfacefor the inclined surfaces'thereof; 'and a,Y Ibolt extending through said bindery andinto said"`t`op ja'w vto draw-said top jaw and binder toward each other.

2. A chuck Vjaw assembly including asupport; a set of equally-'spaced transverse grooves on -each side ofthe'transverse center line Y'of said support; each of the "grooves of one set having an inclined transverse binding surface `-opposed `to a Asimilar surface in each groove Mof -the -other set,` said opposed surfaces 'diverging outwardly; atop 'jaw havinga single integral binding .pro- `jection, rof a width-fle's's-than "the 4width 'of said 4transverse grooves and a mating surface for the lrinclined surface' of said grooves; abinder'separate from sa-idtop .jaw including apotion havhing a. thickness'les's-than' the width of said grooves and a' mating surface for 'the' inclih'ed'surfaces thereof means 'for' locating sa'id top jaw transversely'of said su'p'por-t;` and means `for'drawing said binder andtop jaw'toward-each other such -that 'said portion and binding projection interlockv with said opposedfgrooveslin said support.

3'. A chuckfjawassembly including a support;

"5o a set of equally-spaced straight-line transverse .grooves on each side of the -transverse center lineof said support, each of 'thegrooves of one set having yaninclined'transverse binding Surfaceopp'osedto a similar surface ineach groove o'fthe other-set, said opposed surfacesfdiverging do surface "of said groov'es; 'a 'binder-separate from having an in'clinedtra'nsverse binding surface 'opposed "to a similarsuifacein eachgrooveof theother set, said 'opposed-surfaces? diverging outwardly; a'top-jaw having a single integral binding projection. 'of a width less 'than *the width of said transverse grooves and a straight REFERENCES CITED line transverse mating surface for the inclined surface of said grooves; a binder separate from said top jaw including a. portion having a thick- The following references are of record in the file of this patent:

ness less than the width of said grooves and a 5' UNITED STATES PATENTS straight line mating surface for the inclined sur- Number Name Date faces thereof; means for iocatingsaid top jaw 414.7955 Siweetland Nov. 12, 1889 transversely of said support; and means for draw- FOREIGN PATENTS ing said binder and top Jaw toward each other such that said portion and binding projection 10 Number Country Date interlock with said opposed grooves in said sup- 101866 Sweden 1900 port. 39,934 France 1931 CLIFFORD D. CASSIDY. 

